Prime Minister Justin Trudeau’s government was “insufficiently transparent” about foreign interference in Canadian politics and sometimes took “too long to act’’ against attempts to meddle in the country’s past two general elections by foreign powers including China and India, a government commission said on Tuesday.

“Trust in Canada’s democratic institutions has been shaken, and it is imperative to restore it,’’ the commission said in its final report, which summarized 18 months of hearings, testimony and examination of classified intelligence documents.

The government’s efforts to rebuild trust have been “piecemeal and underwhelming,’’ said Marie-Josée Hogue, a Court of Appeal justice from Quebec, who led the commission.

The final report included 51 recommendations by the commission to strengthen Canada’s electoral system, ranging from stricter rules for the country’s political parties and third-party financing to better sharing of intelligence and oversight of disinformation during campaigns.

Justice Hogue said about half the recommendations “should be implemented promptly, perhaps even before the next election.’’

There Trudeau government had immediate response to the report.

But the recent announcement by Mr. Trudeau, who is deeply unpopular, that he will step down as Liberal Party leader and prime minister makes it unlikely that the commission’s recommendations can be put in place before upcoming elections, experts said. Members of the Liberal Party are expected to elect Mr. Trudeau’s successor by early March, and a general election is likely to take place a couple of months later.

“It seems lamentable that the timeline makes it impossible to implement any of these recommended safeguards,’’ said Ryan Alford, an associate law professor at Lakehead University in Thunder Bay, Ontario. “Sadly and perhaps paradoxically, it’s going to reinforce the notion that the same attempts that occurred in the last two federal elections are inevitably going to take place in this election.’’

The report’s release capped a yearlong public inquiry into foreign interference, which Mr. Trudeau’s government had fiercely opposed. It finally relented only after an extraordinary series of leaks to Canadian news outlets of intelligence reports that revealed Chinese meddling in the past two general elections, in 2021 and 2019.

Months of public hearings, as well as the sworn testimonies of witnesses and the release of intelligence reports, revealed how rising foreign powers — especially China and India — had tried to further their interests in Canada by backing or opposing certain candidates in the elections.

While the elections’ overall outcome was not affected, the interference could have affected a handful of individual races, according to the inquiry commission.

China and India focused their activities in electoral districts in Toronto and Vancouver, where large and well-organized Chinese and Indian diasporas are populated by some of the voters highly sought after by Canada’s political parties. The public hearings showed that China and its proxies tried to undermine candidates of the main opposition Conservative Party, which has adopted a tough line on China’s record on human rights and its control over Hong Kong.

By contrast, the Chinese government and its proxies tended to support candidates of Mr. Trudeau’s Liberal Party, intelligence reports showed. After Mr. Trudeau was first elected in 2015, he pushed for friendly ties with Beijing, including through a free-trade agreement, and dismissed warnings about allowing the Chinese telecommunications company Huawei Technologies to work in Canada.

Witnesses and intelligence reports showed how foreign governments and their proxies tried to influence elections by targeting diaspora members, many of whom have relatives in their countries of origin and also business and other ties. Though diaspora communities were shown to be the focal point of foreign interference, the commission made no strong recommendations about how to protect those voters, said Dennis Molinaro, a former national security analyst for the Canadian government who now teaches legal studies at Ontario Tech University.

“Foreign interference is happening in diaspora communities,’’ Mr. Molinaro said. “If it didn’t happen in diaspora communities, you wouldn’t have foreign interference anywhere else, and the report was relatively quiet about that.’’

Accused of benefiting from Chinese interference, Mr. Trudeau and his government downplayed its threat. But a series of leaks of intelligence reports to The Globe and Mail newspaper and the Global News television network, forced Mr. Trudeau to order the inquiry.

Canada also accused the Indian government of orchestrating the 2023 killing near Vancouver of Hardeep Singh Nijjar, a Canadian leader of the Sikh independence movement in India.

The inquiry showed how foreign powers had exploited weaknesses in Canada’s democratic system, especially in its political parties’ opaque operations. Political parties select candidates for general elections in nomination races with loose rules and no outside oversight.

While party bosses used the system to flex their muscles, the nominations were what the inquiry commission described as “gateways for foreign states who wish to interfere in our democratic processes.”

In one Liberal Party nomination race in a Toronto district with a large Chinese diaspora, buses transported dozens of foreign students from China to back a candidate, Han Dong, who was favored by Beijing.

According to a special parliamentary committee report, the Chinese consulate told the students that they had to vote for Mr. Dong to keep their student visas. Mr. Dong won the nomination in the district, a Liberal stronghold, and then cruised to victory in the general election.

As details of foreign interference emerged in the public hearings, Parliament last summer passed legislation that created a registry of foreign agents and that made it easier to investigate and prosecute foreign meddling.

In the final report, Justice Hogue wrote that “isolated cases where foreign interference may have had some impact on the outcome of a nomination contest or the result of an election in a given” electoral district. But she added that she was “reassured by the minimal impact such efforts have had to date.’’

Duff Conacher, a founder of Democracy Watch, an independent watchdog organization, said the final report underestimates foreign interference, about which much remains unknown.

“Just disinformation alone is having much more than a minimal impact,’’ Mr. Conacher said. “Add to that the documented cases, which are not minimal. And there’s the killing of a Canadian citizen, and the threat that the members of the diaspora of many countries feel. That’s not minimal.’’